The present invention concerns processes for generating trivalent chromium compounds and/or chelates that can be added to animal feeds to provide chromium as an essential trace metal in the animal's diet. This assists in metabolic uptake of glucose, and can boost weight gain in cattle, hogs, sheep, and poultry.
Various processes have been proposed for providing trivalent chromium, and several proposals have been offered for techniques to synthesize chromium propionate as well as other polyvalent metal propionates. Typically the starting materials have been hexavalent chromium compounds, where the chromium needed to be converted first into trivalent form before it could be used as a feed supplement. This typically required a reducing step in which a reducing agent such as a nitrite contacts the chromium source material to convert it from chromium(VI) to chromium(III).
These earlier processes involve heating the materials and require a catalyst to convert the chromium from the hexavalent state to trivalent chromium.